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Postępy w Kardiologii Interwencyjnej 2014; 10, 1 (35)
Short communication
Asymptomatic ST segment elevation in the recovery phase of the exercise stress test due to slow coronary flow
Murat Sunbul, Okan Erdogan, Ibrahim Sari
Department of Cardiology, School of Medicine, Marmara University, Istanbul, Turkey
Postep Kardiol Inter 2014; 10, 1 (35): 53–56 DOI: 10.5114/pwki.2014.41471
A b s t r a c t
Exercise-induced ST segment elevation without Q wave formation is rarely observed. Frequent causes are significant coronary stenosis, myocardial bridge and coronary vasospasm. Both exercise-induced ST segment elevation due to slow coronary flow and ST segment elevation in the recovery phase of the exercise stress test are very rare. We present a 49-year-old man with asymptomatic inferolateral ST segment elevation in the recovery phase of the exercise stress test due to slow coronary flow, which has not been reported previously. The learning points of the present paper are as follows: a) although significant coronary stenosis, myocardial bridge and coronary vasospasm are frequent causes of exercise-induced ST segment elevation, slow coronary flow might also cause it; b) one should keep in mind that ST segment elevation might also occur in the recovery phase; and c) ST segment elevation might be asymptomatic, as in the present case.
Key words: coronary slow flow, ST segment, exercise test, recovery, ischemia.
Introduction
Exercise-induced ST segment elevation without Q wave formation is a rare situation. Frequent causes are significant coronary stenosis, myocardial bridge and coro- nary vasospasm [1–4]. Slow coronary flow is an angio- graphic finding defined as the slow movement of con- trast throughout the coronary lumen in the absence of epicardial coronary stenosis. Exercise-induced ST seg- ment elevation is a very rare situation for patients with slow coronary flow.
We present here a rare case of asymptomatic infero- lateral ST segment elevation in the recovery phase of the exercise stress test due to slow coronary flow, which has not been reported previously.
Case report
A 49-year-old man presented with stable angina for more than 6 months. He had a history of smoking and hyperlipidemia. On admission physical examination, rest- ing electrocardiogram and transthoracic echocardiogra- phy were normal. He underwent a treadmill exercise test with the Bruce protocol. The patient tolerated the exer- cise stress test (he was able to exercise for 9 min and the
Corresponding author:
Murat Sunbul MD, Marmara University Education and Research Hospital, Pendik, Istanbul, Turkey, phone: +90 506 5819015, fax: +90 216 657 06 95, e-mail: drsunbul@yahoo.com.tr
Received: 1.09.2013, accepted: 9.01.2014.
maximal heart rate was 158/min). However, during the recovery period (2 min 57 s after starting the recovery period) he suddenly developed ST segment elevation in leads D2, D3, aVF and V4-6 associated with reciprocal ST segment depression in leads D1, aVL and V1–V3 (Figure 1).
The patient was asymptomatic. After sublingual nitro- glycerin administration ST segment elevation gradually resolved in about 30 min. Coronary angiography (within 45 min of diagnosis) revealed normal coronary arteries with no apparent stenosis. However, coronary flow was significantly slowed in all coronary arteries (Figure 2). The thrombolysis in myocardial infarction (TIMI) frame count was 68 for the left anterior descending artery (normal:
36 ±1), 52 for the circumflex artery (normal: 22.2 ±4) and 44 for the right coronary artery (normal: 20.4 ±3). We planned to perform a provocative test; however, at that time neither ergonovine nor acetylcholine was present in our cath lab. Instead, we performed a hyperventilation test during coronary angiography, which was negative.
The patient was reassured and discharged with acetyl- salicylic acid 100 mg q.d., diltiazem 90 mg b.i.d., atorvas- tatin 20 mg q.d. and isosorbide mononitrate 40 mg b.i.d.
Postępy w Kardiologii Interwencyjnej 2014; 10, 1 (35) Murat Sunbul et al. Asymptomatic ST elevation in recovery phase of exercise test
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A
Figure 1. A – Exercise stress test during maximal exercise. B – Exercise stress test at recovery phase with ele- vated ST segments in leads D2, D3, aVF, V4–V6 and depressed ST segment in leads D1, aVL, V1–V3
B
Postępy w Kardiologii Interwencyjnej 2014; 10, 1 (35)
Murat Sunbul et al. Asymptomatic ST elevation in recovery phase of exercise test
55 Discussion
In the present paper, we report a 49-year-old man with asymptomatic inferolateral ST segment elevation in the recovery phase of the exercise stress test due to slow coronary flow, which has not been reported previously.
Exercise-induced ST segment elevation without Q wave formation is rarely observed. Its frequent caus- es are significant coronary artery stenosis, myocardial bridge and coronary vasospasm [1–4]. Exercise-induced ST segment elevation is a very rare situation for patients with slow coronary flow. To date, there is only one paper reporting exercise-induced ST segment elevation due to slow coronary flow [5]. One of the interesting points of the present case is the occurrence of ST segment ele-
vation in the recovery phase of exercise stress, which is even more rare [6].
One possible etiologic explanation for the present case is coronary vasospasm. However, clinical and an- giographic findings were not compatible with variant angina. The patient did not describe any anginal epi- sodes at rest, especially during the morning. Addition- ally, the coronary angiogram of our patient was angi- ographically normal without any apparent stenosis.
In the majority of patients with coronary vasospasm, significant eccentric proximal coronary obstruction of at least one coronary artery has been reported [5]. For these reasons we considered that ST elevation occurred due to slow coronary flow.
Figure 2. Right cranial view of left anterior descending and circumflex arteries during filling (A) and wash-out phase (B). Right anterior oblique view of right coronary artery during filling (C) and wash-out phase (D)
C D
A B
Postępy w Kardiologii Interwencyjnej 2014; 10, 1 (35) Murat Sunbul et al. Asymptomatic ST elevation in recovery phase of exercise test
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Conclusions
The learning points of the present paper are as fol- lows: a) although significant coronary stenosis, myocar- dial bridge and coronary vasospasm are frequent causes of exercise-induced ST segment elevation, slow coronary flow might also cause it; b) one should keep in mind that ST segment elevation might also occur in the recovery phase; and c) ST segment elevation might be asymptom- atic, as in the present case.
References
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4. Kapoor A, Goel PK, Gupta S. Slow coronary flow – a cause for angina with ST segment elevation and normal coronary arteries.
A case report. Int J Cardiol 1998; 67: 257–261.
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